JP2003156441A - Method and device for inspecting quality inside fruit and vegetable - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a technique capable of discriminating easily internal deterioration of fruits and vegetables, in particular, the internal deterioration accompanied with discoloration such as browning. SOLUTION: An apple is irradiated with light, the light intensities in peak wavelength bands within 810 nm±20 nm of near infrared area and 710 nm±30 nm of visible ray area are measured in a spectral intensity distribution of transmitted rays transmitted through the apple, specific intensity of the light intensity in the peak wavelength band within the visible ray area to the light intensity in the peak wavelength band within the near infrared area is calculated, and the internal quality of the apple is discriminated based on combination of the light intensity in the peak wavelength band within the visible ray area, and the specific intensity.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for nondestructively inspecting the internal quality of fruits and vegetables and an apparatus therefor, and more particularly to an inspection technique using transmitted light of fruits and vegetables.

[0002]

2. Description of the Related Art Conventionally, the internal quality of fruits and vegetables has been empirically determined by the appearance of the shape and color of the fruits and vegetables, or by visual inspection by cutting a sample taken. However, internal quality is often difficult to distinguish from the outside, and
The fruits and vegetables subjected to the sampling inspection have no commercial value, and the internal quality of the remaining fruits and vegetables can only be estimated from the results of the sampling inspection.

Therefore, in recent years, a technique for discriminating the internal quality of fruits and vegetables by using a spectroscopic method has been proposed. For example, fruits generally have higher commercial value as the sugar content is higher. Therefore, for example, Japanese Patent Application Laid-Open No. 4-104041 describes a method of inspecting the internal quality such as sugar content of fruits and vegetables from the intensity of transmitted light in a specific wavelength region.

Further, a fully-ripened apple product is in a so-called honey-containing state and emits a unique aroma and taste, and is preferred as a high-grade product. So, for example, "Fruit Tree Trial C15 P
14-47 Ministry of Agriculture, Forestry and Fisheries 1988 ”describes a method for nondestructive measurement of nectar symptoms of apple fruits by light transmission of a single wavelength. Thus, by measuring the transmitted light of fruits and vegetables, it is possible to nondestructively inspect the sugar content and the honey-filled state of fruits and vegetables such as apples.

[0005]

By the way, in recent years, a technique has been developed for storing fruits and vegetables such as apples for a long period of time by controlling temperature and atmospheric gas while maintaining their freshness. As a result, fruits and vegetables can be shipped in seasons other than the season.

However, when fruits and vegetables such as apples are stored for a long period of time, the flesh may turn brown (browning) and the aroma and taste may be lost. The transmittance of fruits and vegetables that have undergone internal deterioration such as browning generally decreases.

On the other hand, the transmittance of fruits and vegetables is higher as the water content of the pulp is higher, and as the water content is lower, scattering tends to increase and the transmittance tends to decrease. Here, in FIG.
An example of the change over time of the transmission spectrum of an apple is shown. The horizontal axis of the graph of FIG. 3 represents wavelength (nm), and the vertical axis represents light intensity (count number). Curve IV in the graph is
2 shows a transmission spectrum of a fresh apple. The broken line V represents the transmission spectrum of the same apple after the number of days has passed. Then, as indicated by the curve IV and the broken line V, the water content of the pulp decreases with the lapse of days, and therefore the spectrum intensity as a whole decreases. The characteristic of this transmission spectrum is 780 nm to 830 in the near infrared region.
There is a peak wavelength band having one peak in nm, and there are two peak wavelength bands in the vicinity of 630 nm and 700 nm in the visible light region of 550 nm to 780 nm.

Therefore, the transmittance tends to decrease even when the honey containing honey is low. As a result, it is difficult to discriminate between apples that have undergone internal deterioration such as browning and apples that have reduced nectar by simply measuring the transmittance, as in the above-mentioned conventional technique.

The present invention has been made in view of the above circumstances, and an object thereof is to provide a technique capable of easily discriminating the internal quality of fruits and vegetables, particularly the internal deterioration accompanied by discoloration such as browning.

[0010]

In order to achieve the above object, the inventor of the present invention has conducted various studies and experiments and as a result, when the water content of fruits and vegetables has simply decreased, As shown in 3, when the transmittance in both the near-infrared region and the visible light region is reduced at the same rate, in the case where an internal disorder accompanied by discoloration such as browning occurs in fruits and vegetables,
The present invention has been conceived, paying attention to the fact that the transmittance in the visible light region is significantly lower than that in the near infrared region.

Therefore, according to the method for inspecting the internal quality of fruits and vegetables according to claim 1 of the present invention, the spectral intensity distribution of the transmitted light from the fruits and vegetables irradiated with light is compared with the light intensity in the peak wavelength band in the near infrared region. This is a method for determining the internal quality of the fruits and vegetables based on a combination of the specific intensity of the light intensity in the peak wavelength band of the visible light region and the light intensity in the peak wavelength band of the visible light region.

As described above, according to the present invention, in the internal alteration accompanied by discoloration such as browning, the transmitted light intensity in the visible light region is much lower than the transmitted light intensity in the near infrared region. The internal quality is inspected by combining the transmitted light intensity and the specific intensity in the peak wavelength band which is the peak of the visible light region with respect to the near infrared region. Accordingly, even when it is difficult to determine the internal quality only by the transmitted light intensity or the specific intensity, it is possible to easily determine the internal alteration accompanied by discoloration such as browning.

According to the second aspect of the invention, the peak wavelength band in the visible light region is 550 nm ± 30 nm,
600nm ± 30, 630nm ± 30nm, 700nm
At least one wavelength band is selected from the group of ± 30 nm or 730 nm ± 30 nm, and the light intensity thereof is measured. On the other hand, as the peak wavelength band in the near infrared region,
This is a method of selecting 800 to 810 nm ± 30 nm and measuring the light intensity thereof.

The transmission spectrum of many kinds of fruits and vegetables such as apples is about 700 nm in the visible light region, 60.
It has been found that there is a peak wavelength band near 0 nm to 630 nm and around 550 nm, and particularly the intensity near 700 nm is high. In the near infrared region, 80
It has been found that a peak serving as a peak is formed at ± 30 nm centered on 0 nm to 810 nm, that is, at 770 nm to 840 nm. Therefore, if the light intensities of these wavelengths are measured, it becomes easier to determine the internal quality.

Further, according to the internal quality inspection apparatus for fruits and vegetables according to claim 3 of the present invention, a light source for irradiating the fruits and vegetables to be inspected with light, a spectroscopic means for wavelength-splitting the transmitted light of the fruits and vegetables, and a near infrared ray. Light intensity measuring means for measuring the light intensity in the peak wavelength band of the visible region and visible light region, and a ratio for calculating the ratio of the light intensity in the peak wavelength band of the visible light region to the light intensity in the peak wavelength band of the near infrared region The intensity calculation means and the determination means for determining the internal quality of fruits and vegetables based on the combination of the light intensity and the specific intensity in the peak wavelength band of the visible light region are provided.

As described above, according to the present invention, even when it is difficult to determine the internal quality only by the transmitted light intensity or the specific intensity, the transmitted light intensity and the light intensity in the near infrared region are used as references. It is possible to easily determine the internal quality by combining with the specific strength. In particular, internal alteration accompanied by discoloration such as browning can be easily identified.

According to a fourth aspect of the invention, the spectroscopic means includes at least one demultiplexing means for demultiplexing the transmitted light in two directions, and the demultiplexed light enters to detect the visible light region. One or more visible light wavelength filters that selectively transmit light in the desired wavelength band, and a near-infrared wavelength filter that receives another demultiplexed light and selectively transmits light in the near-infrared wavelength band The light intensity measuring means comprises one or more first optical sensors for measuring the light intensity of the transmitted light of the first wavelength filter, and a first light sensor for measuring the light intensity of the transmitted light of the second wavelength filter. It is composed of two optical sensors.

Thus, the transmitted light intensity in the visible light region,
If the transmitted light intensities in the near infrared region are individually measured, these transmitted light intensities can be simultaneously measured. For this reason,
It is possible to inspect the internal quality of a large amount of fruits and vegetables in a short time.

According to the invention of claim 5, the wavelength band to be detected in the visible light region is 550 nm ± 30 n.
m, 600 nm ± 30, 630 nm ± 30 nm, 700
nm ± 30 nm or 730 nm ± 30 nm, and at least one wavelength band is selected from the group of wavelengths of 800 to 810 nm ±.
The configuration is such that 30 nm is selected.

The transmission spectra of many kinds of fruits and vegetables such as apples are in the visible light region around 700 nm, 60
It has been found that there is a peak wavelength band near 0 nm to 630 nm and around 550 nm, and particularly the intensity near 700 nm is high. In the near infrared region, 80
It has been found that peaks forming peaks are formed near 0 nm to 810 nm. Therefore, if the light intensities of these wavelengths are measured, it becomes easier to determine the internal quality.

[0021]

BEST MODE FOR CARRYING OUT THE INVENTION An embodiment of an internal quality inspection method and apparatus (also abbreviated as "discrimination apparatus") of fruits and vegetables according to the present invention will be described below with reference to the drawings. The configuration of the discriminating apparatus will be described with reference to the discriminating apparatus of the present embodiment, which includes a light source 1, a condenser 3, a non-polarizing beam splitter 4, and first and second wavelength filters 5a.
And 5b, the first and second optical sensors 6a and 6b, the specific intensity calculator 7 and the discriminator 8.

A xenon lamp or a halogen lamp may be used as the light source 1. These light sources have an emission spectrum over a wavelength band including a wavelength for measuring light intensity. The irradiation light may be emitted continuously or intermittently. Further, the first and second optical sensors 6a and 6b use silicon photodiodes having a spectral sensitivity from the visible light region to the near infrared light region,
The present invention is not limited to this, and may be a photomultiplier tube, a solar cell or the like as long as it has the required spectral sensitivity.

The light emitted from the light source 1 is applied to the fruits and vegetables 2 to be inspected. In this embodiment, the internal quality of apples as fruits and vegetables 2 is inspected. The apple has peak wavelength bands that are large peaks of the transmission spectrum in the range of ± 30 nm centered at 710 nm in the visible light region and in the range of ± 20 nm centered at 800 nm in the infrared region. The transmitted light of the fruits and vegetables 2 is condensed by the condenser 3 and is incident on the non-polarization beam splitter 4. The non-polarization beam splitter 4 splits the transmitted light by transmitting a part of the incident light and laterally reflecting the remaining part.

One of the demultiplexed transmitted lights enters the first wavelength filter 5a. The first wavelength filter 5a is 690
It is a narrow band interference filter of ˜730 nm and selectively transmits only the light in the range of 690 to 730 nm in the visible light region of the incident transmitted light. The light transmitted through the first wavelength filter 5a enters the first optical sensor 6a. First optical sensor 6
a measures the light intensity of the transmitted light of the first wavelength filter 5a. The measurement result is output as the first light intensity signal.

Further, the other split transmitted light is incident on the second wavelength filter 5b. The second wavelength filter 5b is
It is a narrow band interference filter of 790 nm to 830 nm, and 790 nm to 830 nm in the infrared region of incident transmitted light.
Only the light in the range is selectively transmitted. The light transmitted through the second wavelength filter 5b enters the second optical sensor 6b. The second optical sensor 6b measures the light intensity of the transmitted light of the second wavelength filter 5b. The measurement result is output as the second light intensity signal.

In the present embodiment, the non-polarizing beam splitter 4, the first and second wavelength filters 5a and 5b are
It constitutes a spectroscopic unit, and the first and second optical sensors 6a and 6b constitute a light intensity measuring unit.

The first and second light intensity signals are input to the specific intensity calculator 7. In the specific intensity calculation unit 7, the specific intensity of the first optical intensity signal with respect to the second optical intensity signal, that is, the specific intensity of the optical intensity in the peak wavelength band of the visible light region with respect to the optical intensity in the peak wavelength band of the near infrared region To calculate. The calculation result is output as a specific intensity signal.

The specific intensity signal is input to the discrimination unit 8. The first light intensity signal is also input to the determination unit 8. Then, the determination unit 8 determines the internal quality of the fruit 2 based on the combination of the light intensity in the peak wavelength band of the visible light region and the specific intensity, that is, the combination of the first light intensity signal and the specific intensity signal. To do.

Here, FIG. 2 shows an example of the light intensity and the specific intensity of the transmitted light of the apple. Here, apples with honey, but with a moderate browning of honey (honey browning (medium) apples),
The internal qualities of three types of apples, that is, an apple in which a part of the inside is browned (medium browned apple) and an apple in which a large part of the inside is browned (a large browned apple) are determined.

FIG. 2A is a graph showing the wavelength spectrum of the transmitted light of the apple. The horizontal axis of the graph is the wavelength (n
m) and the vertical axis represents the light intensity. Here, the light intensity is represented by an arbitrary count number. The curve Ia in the graph represents the transmission spectrum of the nectar browning (medium) apple, the broken line IIa represents the transmission spectrum of the medium browning apple, and the alternate long and short dash line IIIa represents the transmission spectrum of the large browning apple. .

As shown by the curve Ia, the transmission spectrum of the nectar-brown (medium) apple has a high peak intensity of 540 (count number) in the visible light region of 690 to 730 nm. On the other hand, as shown by the broken line IIa,
In the medium browning apple, the peak intensity is reduced to 380 (count number). Further, as shown by the alternate long and short dash line IIIa, in the large browning apple, the peak intensity is significantly reduced to 150 (count number). Therefore, it can be seen that the peak intensity in the visible light region is extremely high in an apple with brown nectar and is greatly reduced when the pulp is browned.

By the way, as shown by the curve Ia, in the nectar browning (medium) apple, the peak intensity in the infrared region of 790 nm to 830 nm is also high, but as shown by the broken line IIa and the alternate long and short dash line IIIa, For browned apples,
The peak intensities in the infrared region are as low as each other.

Therefore, FIG. 2B shows a standardized spectrum in which the peak intensity in the infrared region is "1". The horizontal axis of the graph in FIG. 2 represents wavelength (nm), and the vertical axis represents specific intensity (relative value). The curve Ib in the graph represents the normalized spectrum of the nectar browning (medium) apple, and the broken line IIb
Represents the normalized spectrum of medium browning apple, and the alternate long and short dash line IIIb represents the normalized spectrum of large browning apple.

As shown by the broken line IIb, the specific intensity of the peak intensity in the visible light region to the peak intensity in the infrared region of the medium browning apple is 1.7. On the other hand, as shown by the curve Ib, the specific strength of the nectar browning (medium) apple is 1.1. Further, as shown by the alternate long and short dash line IIIb, the specific intensity of the large browning apple is 0.8.

Therefore, by combining the light intensity shown in FIG. 2A and the specific intensity shown in FIG. 2B, the internal quality of the apple can be determined. For example, in the case of a honey browning (medium) apple, the light intensity is high as 540 (count number) as shown by the curve Ia, and the specific intensity is 1.1 as medium as shown by the curve Ib. . On the other hand, in the case of the medium browning apple, the light intensity is medium as 380 (count number) as shown by the broken line IIa, and the specific intensity is high as 1.7 as shown by the broken line IIb. Has become. Further, in the case of the large browning apple, the light intensity is as low as 150 as shown by the one-dot chain line IIIa, and the specific intensity is as low as 0.8 as shown by the one-dot chain line IIIb. Thereby, from the combination of light intensity and specific intensity,
It is possible to easily discriminate between the nectar browning (medium) apples, the medium browning apples, and the large browning apples.

In the above-described embodiment, the example in which the present invention is configured under a specific condition has been described, but the present invention can be variously modified. For example, in the above-described embodiment, an example has been described in which apples are used as the fruits and vegetables to be inspected, but in the present invention, the inspection targets are not limited to apples. For example, fruits such as citrus fruits such as tangerines and bananas, root vegetables such as radish and potatoes, and annual fruits such as eggplant, cucumber, tomato or melon and pineapple are also suitable for inspection.

For example, as shown by the curve VI in the graph of FIG. 4, the transmission spectrum of banana is 70% in the visible light region.
A peak is formed near 0 nm and near 810 nm in the near infrared region. In addition, as shown by the broken line VII in the graph of FIG.
A peak is formed near 10 nm and near 810 nm in the near infrared region. Also, for example, in the graph of FIG.
As indicated by II, the transmission spectrum of cucumber has peaks near 550 nm and 750 nm in the visible light region, and has a peak wavelength band as a shoulder of the peak near 810 nm in the near infrared region. Also, FIG.
As indicated by a broken line IX in the graph of No. 3, the orange transmission spectrum also has peaks near 700 nm in the visible light region and around 810 nm in the near infrared region. Therefore, the present invention can be applied to these fruits and vegetables.

Further, for example, in the above-described embodiment, an example in which the light intensity within the range of 690 to 730 nm is measured as the visible light region has been described, but in the present invention, the peak wavelength band in the visible light region other than this is described. The light intensity of may be measured. Also, a plurality of peak wavelength bands may be measured as the visible light region.

[0039]

As described above in detail, according to the present invention, the transmitted light intensity and the specific intensity can be determined even if it is difficult to determine the internal quality only by the transmitted light intensity or the specific intensity. By combining them, the internal quality can be easily determined. In particular, internal alteration accompanied by discoloration such as browning can be easily identified.

[Brief description of drawings]

FIG. 1 is a block diagram illustrating a configuration of an internal quality inspection device for fruits and vegetables according to an embodiment.

FIG. 2A is a graph showing a measurement result of a transmitted light spectrum, and FIG. 2B is a graph obtained by normalizing the measurement result shown in FIG.

FIG. 3 is a graph showing changes with time of a transmitted light spectrum.

FIG. 4 is a graph showing transmission spectra of banana and tomato.

FIG. 5 is a graph showing transmission spectrums of cucumber and orange.

[Explanation of symbols]

1 light source 2 fruits and vegetables 3 light collector 4 Non-polarizing beam splitter 5a, 5b Wavelength filter 6a, 6b optical sensor 7 Specific strength calculator 8 Judgment section

   ─────────────────────────────────────────────────── ─── Continued front page    (72) Inventor Hodaka Fukahori             22-4 Okazawa-cho, Hodogaya-ku, Yokohama-shi, Kanagawa               Toyo Seikan Group General Research Institute F term (reference) 2G051 AA05 AB06 BA06 CB02 CC07                       EB01                 2G059 AA05 BB11 EE01 EE12 GG08                       HH01 HH02 HH06 JJ02 JJ03                       JJ22 KK02 KK03 MM01 MM05

Claims (5)

[Claims] 1. A spectral intensity distribution of transmitted light from fruits and vegetables irradiated with light, which is a ratio of the light intensity in the peak wavelength band of the visible light region to the light intensity in the peak wavelength band of the near infrared region, and the visible light region. The method for inspecting the internal quality of fruits and vegetables, wherein the internal quality of the fruits and vegetables is determined on the basis of the combination with the light intensity in the peak wavelength band. 2. The peak wavelength band of the visible light region,
550nm ± 30nm, 600nm ± 30, 630nm
± 30 nm, 700 nm ± 30 nm or 730 nm
At least one wavelength band is selected from the group of ± 30 nm, and the light intensity thereof is measured, while the peak wavelength band in the near infrared region is 800 to 810 nm ± 3.
The method for inspecting the internal quality of fruits and vegetables according to claim 1, wherein 0 nm is selected and the light intensity thereof is measured. 3. A light source for irradiating the fruits and vegetables to be inspected with light, a spectroscopic means for wavelength-splitting the transmitted light of the fruits and vegetables, and a light intensity for measuring the light intensity in the peak wavelength band of the near infrared region and the visible light region. Measuring means, a specific intensity calculation means for calculating the specific intensity of the light intensity in the peak wavelength band of the visible light region to the light intensity in the peak wavelength band of the near infrared region, the light intensity in the peak wavelength band of the visible light region and the An internal quality inspection device for fruits and vegetables, comprising: a determination unit that determines the internal quality of the fruits and vegetables based on a combination with a specific intensity. 4. The spectroscopic means selectively outputs at least one demultiplexing means for demultiplexing the transmitted light in two directions and light in a wavelength band to be detected in a visible light region upon incidence of the demultiplexed light. , One or more visible light wavelength filters that are transmitted through, and another demultiplexed light is incident, and is configured by a near-infrared wavelength filter that selectively transmits light in the wavelength band of the near-infrared region. The intensity measuring means includes one or more first optical sensors that measure the light intensity of the transmitted light of the first wavelength filter, and a second optical sensor that measures the light intensity of the transmitted light of the second wavelength filter. The internal quality inspection device for fruits and vegetables according to claim 3, wherein 5. The wavelength band to be detected in the visible light region is 550 nm ± 30 nm, 600 nm ± 30, 630.
nm ± 30 nm, 700 nm ± 30 nm or 730
nm ± 30 nm, at least one wavelength band is selected from the group, while as the peak wavelength band in the near infrared region,
The internal quality inspection device for fruits and vegetables according to claim 3 or 4, wherein 800 to 810 nm ± 30 nm is selected.